City water profile
Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for St. Charles, Missouri.
Median indexed hardness
257PPM
2 indexed ZIPs
Range 256.5–256.5 PPM
City summary
St. Charles has 2 published ZIP profiles across St. Charles County. The indexed median is 257 PPM, compared with 236 PPM across Missouri.
Among the 504 Missouricities with an indexed median, St. Charles ranks #197from highest to lowest. Across all 556 state ZIP profiles, available estimates run from 38.3to 483 PPM.
The 256.5–256.5 PPM range shows how much the available ZIP estimates vary within the city label.
Hardness distribution
2 of 2 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.
Evidence quality
Confidence labels
Observation window: Jan 6, 2016 to Jun 9, 2026.
ZIP directory
Open a ZIP for site-level provenance and measurements.
Public water systems
PWSID MO6010707
The system names this served city; Census place overlap links the city to this ZCTA.
Compliance history
No active health-based violation appears among the associated systems in the represented EPA reporting quarter. This does not mean every contaminant was tested at every tap.
| Record | System | Period | Status |
|---|---|---|---|
| Lead and Copper Rule | MO6010707 | Oct 1, 2024 | Resolved |
Practical next steps
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Questions people ask
The indexed city median is 257 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.
Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.
Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.